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Oliver Bailey and Pradyumna Raval
running anteroinferiorly to the proximal tibia
at a site midway between Gerdy’s tubercle
and the head of the fibula
C. The anterolateral ligament was originally
identified by Gerdy in 1879
D. The entire anterolateral ligament is visible
from its proximal insertion to its distal insertion, with excellent agreement between ultrasound and anatomical findings
E. The sensitivity of an MRI scan in detecting an
anterolateral injury ranges from 80–90%
41. A 35-year-old dance teacher is referred to your
elective knee clinic with a complaint of pain in
her knee which has been ongoing for 3 months.
There is no history of antecedent trauma. She
does not have any mechanical symptoms of her
knee locking; however she is quite distressed by
what she describes as a ‘disappearing’ swelling on
the outer (lateral) aspect of her knee.
What is this lady suffering from?
A. A ganglion on the lateral aspect of the knee
B. A lateral meniscal cyst
C. Lateral meniscus tear
D. Snapping iliotibial band syndrome
E. Symptomatic discoid meniscus
42. A 35-year-old dentist is referred to your clinic with
a 6-month history of anterior knee pain. The dentist tells you that he fell while running and the
anterior aspect of his right knee took the impact
of the fall. He ever since has a constant ache and
discomfort in the anterior aspect of his knee
worsened by activities. He sometimes feels a
clicking sensation on flexion and extension of his
knee. Imaging investigations do not help much in
the diagnosis and conservative treatment has failed.
You decide to perform a knee arthroscopy.
What is the cause of his symptoms?
A. Infra-patellar plica
B. Lateral patellar plica
C. Medial patellar plica
D. Patello-femoral arthritis
E. Supra-patellar plica
43. You are consenting a young football player about
anterior cruciate ligament reconstruction surgery. This young man does not want his hamstring tendon or bone-patellar tendon-bone
graft. He wants to know about allograft for
ACL reconstruction.
Which of the following statements is
incorrect?
A. Allograft maturation takes longer than auto-
graft maturation
B. Increased use of allografts in primary proced-
ures is making it more difficult to obtain
these for revision or for multiple ligament
procedures
C. The failure rate of allografts is similar to
autografts
D. The potential for infection with allograft is
low
E. Use of allografts decreases post-operative
morbidity
44. A 3rd year orthopaedic registrar injures his knee
while playing football and MRI scan reveals that
he has an anterior cruciate ligament injury. He
consults you in your clinic and wishes to
undergo ACL reconstruction surgery. He is
happy for you to use an autograft but requests
you to use the strongest autograft which has a
high ultimate strength to failure.
What advice would you give him?
A. Allografts are stronger than autografts and
have higher ultimate strength to failure
B. Bone patellar tendon bone is the strongest
graft of all known ACL autografts
C. Quadriceps tendon graft is stronger than
patellar tendon and quadrupled hamstring
tendon
D. Quadrupled hamstring tendon graft is the
strongest at 4140 Newton
E. There is no difference in the ultimate strength
to failure of any grafts
45. Studies involving gene therapy have shown
promising results in treatment of knee osteoarthritis in animal models. The cytokine Interleukin1 (IL-1) is highly expressed in chroni c inflammatory conditions such as rheumatoid arthritis and
osteoarthritis. The IRAP gene is interleukin-1
receptor antagonist protein.
Inhibition of cartilage breakdown has been
shown by insertion of?
A. Interleukin-10 (IL-10)
B. IRAP gene alone
C. Simultaneously injecting IRAP and IL-10
D. TGF-β1
E. Vascular endothelial growth factor (VEGF)
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Knee I Structured SBA
46. You examine a 40-year-old medical secretary with
a 3-day-old history of twisting injury to her knee.
She tells you that her symptoms have improved
significantly. On examination you do not find any
specific area of tenderness around the knee. You
decide to discharge her with an open appointment. Your SHO wants to know why you did
not request a knee radiograph for this lady. You
explain to your SHO that she does not fit the
OTTAWA criteria for a knee radiograph.
Which one of the following is not an OTTAWA
criterion for a radiograph in a traumatic knee
injury?
A. Age >70 years
B. Inability to bear weight immediately after
injury
C. Inability to flex the knee to 90°
D. Isolated patellar tenderness
E. Tenderness at the head of fibula
47. On a busy on call in a major trauma centre you get
called to review a labourer who has fallen off a
height. The air ambulance team is concerned about
a potentially dislocated right knee. On initial evaluationthe patient isconscious with a GCS of15. You
then examine the knee and find it to be in an
anatomic alignment with a good palpable pulse.
With regards to the vascular injury in a knee dislocation which of the following statements is true?
A. Amputation rates increase dramatically when
revascularisation is delayed for more than 12
hours
B. Anterior dislocations are more often associ-
ated with intimal injuries because of vessels
getting stretched over the distal femur
C. Lower Extremity Assessment Project (LEAP)
study had reported a 50% incidence of amputation in patients with a knee dislocation and
vascular injury
D. The posterior tibial artery is the primary
vessel supplying the knee joint
E. The rate of arterial injury is different in
anterior and posterior dislocation
48. In the above patient a vascular injury is ruled
out. Further imaging in the form of an MRI scan
reveals that he has multi-ligament injury involving the anterior and posterior cruciate ligament.
You discuss management options with him. He
would like to consider surgery. While explaining
common complications you mention about stiffness of the knee, instability, any missed fractures,
early arthritis and heterotrophic ossification.
Which of the following statements is true about
HO formation in a case of knee dislocation?
A. An open surgical procedure is mandatory to
address the HO formation
B. Heterotrophic ossification (HO) occurs in all
cases of knee dislocation
C. Knee stiffness in these patients improves over
time without requiring any additional procedure
D. Posterior cruciate ligament reconstruction has
a strong association with formation of HO
E. Radiotherapy is advised in all patients with
knee dislocation to reduce the incidence of
HO formation
49. A Core trainee approaches you asking for an
audit project. You advise her to gather data about
patients who were diagnosed with gout in the
past 6 months. The data reveal that gout in
women generally presents after menopause as
compared with men who are relatively younger
when diagnosed with gout.
Which of the following statements with regards
to pathophysiology of gout is true?
A. Eating seafood such as sardines, mackerel and
herring is healthy and does not cause gout
B. Oestrogen is uricosuric
C. Testosterone is uricosuric
D. There is no association of sex hormones with
gout
E. Urate clearance is independent of kidney
function
50. A 68-year-old lady is referred to your elective
Orthopaedic clinic with a long-standing history
of right knee pain. Conservative measures have
failed, and she wishes to undergo a joint replacement procedure. On inspection you notice a large
psoriatic patch on the anterior aspect of her knee.
Which of the following is not a part of the
CASPAR criteria for psoriatic arthritis?
A. A current psoriatic skin or scalp lesion with a
family history of psoriasis
B. Current dactylitis or previous history of dac-
tylitis as reported by a rheumatologist
C. Positive test for rheumatoid factor
D. Psoriatic nail dystrophy including pitting,
onycholysis and hyperkeratosis
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Oliver Bailey and Pradyumna Raval
E. Radiological evidence of juxta-articular new
bone formation
51. On a busy Orthopaedic on call you get called by
the Paediatric Registrar requesting you to review
a neonate with abnormal position of his knee.
You examine this baby and diagnose that this
child has a congenital dislocation of his knee.
With regards to congenital dislocation of the
knee (CDK) which of the following statements
is incorrect?
A. Abnormal foetal position can lead to a uni-
lateral CDK
B. Bilateral CDK is never associated with any
syndromes
C. Clubfoot and hip dysplasia are commonly
associated conditions
D. Hypoplasia of the patella and iliotibial band
contracture may be present
E. One extended and one flexed knee can be
present in neurological conditions such as
arthrogryposis
52. You are consenting a 65-year-old former beautician for a total knee replacement procedure.
This patient tells you that she is allergic to nickel,
and you assure her that you will use components
in surgery which do not have nickel in them.
With regards to the genetic aetiology of contact
sensitisation, null mutations in which polypeptide are associated with nickel allergy?
A. Cecropin
B. Filaggrin
C. Integrin
D. Magainin
E. Saporin
53. The ED refers a 25-year-old to you with a history
of traumatic right knee pain and swelling. You
take a detailed history and note that this young
man suffers from a bleeding disorder. His radiographs show a ‘squared patella’ .
What is the commonest type of this bleeding
disorder and how is it inherited?
A. Factor VII deficiency and X-linked dominant
B. Factor VIII deficiency and X-linked dominant
C. Factor VIII deficiency and X-linked recessive
D. Factor IX deficiency and autosomal
dominant
E. Factor IX deficiency and X-linked dominant
54. A 35-year-old chartered accountant presents to
you with a history of right knee pain and swelling.
There is no history of trauma. Blood investigations
are within normal limits. Radiographs do not show
any obvious bony abnormality. You organise an
ultrasound examination which reveals a markedly
thickened synovium, but the radiologist advises an
MRI scan for understanding the pathology better.
MRI scan reveals a prominent low signal intensity on T2-weighted images and a ‘blooming’
artefact from haemosiderin seen with gradientecho sequences.
What is this young man suffering from?
A. Haemophilia A
B. Haemophilia B
C. Non-specific synovitis of the knee joint
D. Pigmented villonodular synovitis
E. Synovial sarcoma
55. You review a 64-year-old retired army personnel
in your elective clinic. This patient has been
referred by his general practitioner for consideration of bilateral knee arthroplasty. The patient is
keen to undergo both knee replacement surgeries
in the same sitting (SBTKA – simultaneous bilateral total knee arthroplasty) because his friend
had a good outcome from such a procedure. You
discuss the procedure in detail and consent him.
Which of the following statements is incorrect
about SBTKA?
A. Haemoglobin of less than 11g/dl and
Jehovah’s Witness patients should not be
offered SBTKA
B. On comparing SBTKA with staged bilateral
total knee replacements 3 months apart, fit
and healthy patients undergoing SBTKA have
equivalent or better outcomes than those who
undergo staged BTKA
C. Patients undergoing SBTKA have a lower
post-operative 30-day mortality rate
D. Patients undergoing SBTKA have faster
return to work, faster recovery and lower
overall pain medication requirement
E. Simultaneous bilateral tourniquet deflation
has shown reperfusion injury and has
resulted in cases of cardiac arrest immediately
after deflation
56. On a busy Orthopaedic on-call you are referred a
case of a newborn with an abnormal-looking
116
Knee I Structured SBA
knee joint. You review the patient and diagnose
this condition as a case of ‘congenital dislocation
of the knee’.
Which of the following is not associated with
congenital dislocation of the knee?
A. Abnormal foetal malposition of hyperflexion
B. Congenital absence of the cruciate ligaments
C. Fibrosis of the quadriceps
D. Intrauterine ischaemia causing compartment
syndrome – like fibrosis
E. Maternal history of herpes
57. You review a9-year-old child inyour elective clinic
with a vague historyof pain in his knee. There is no
known history of trauma and blood investigations
are within normal limits. Your working diagnosis
is that of osteochondritis dissecans.
While examining this patient you flex his knee to
90°, then internally rotate the tibia as the knee is
extended from 90° toward f ull extension. The patient
haspainatapproximately30°shortoffullextension.
What is the name of this clinical sign?
A. Destot’s sign
B. Grey Turner’s sign
C. Gower’s sign
D. Kehr ’s sign
E. Wilson’s sign
58. A retired football player is referred to your elect-
ive clinic with a history of bilateral knee pain.
Radiographs reveal that he has advanced osteoarthritis. The patient tells you that he always had
slightly ‘curved’ knees since childhood but had
no concerns and played football at a very competitive level. He wants to discuss the need for
knee arthroplasty surgery.
With regards to restoration of alignment in
this particular case, which of the following
statements is true?
A. Development of varus knee deformity is due
to incr eased compression on the medial side
and accelerated growth on the lateral side.
This is explained by Wolff’ s law
B. In the classic alignment philosophy the sur-
geon aims to obtain a perpendicular implant
position with reference to the anatomical axis
of tibia and femur in the coronal plane
C. Intense sporting activi ties during growth
leads to varus knees and this typically occurs
during the end of growth spurt
D. ‘K inematic alignment’ and ‘constitutional
alignment’ are two different types of knee
alignments
E. Perpendicular cuts on the distal femur and
tibia do not change the orientation of the
medial and lateral joint lines
59. You are consenting a patient for total knee
arthroplasty and explain about the potential
complication of extensor mechanism disruption.
With regards to quadriceps tendon rupture
which of the following statements is false?
A. Chronic kidney disease is not a risk factor for
quadriceps rupture
B. Patients with diabetes mellitus have a higher
risk of quadriceps rupture
C. Patients with rheumatoid arthritis have a
higher risk of quadriceps rupture
D.
Previous multiple knee surgeries are a known
risk factor
E. The incidence of quadriceps rupture is less
than 1%
60. You consult a 55-year-old lady with posttraumatic knee arthritis for a total knee arthroplasty. This patient was in a road traffic accident
years ago and injured her knee which led to the
early onset of osteo-arthritis. She tells you that
she lost a dear friend in that accident and has
been on antidepressants since then. She also has a
history of fibromyalgia. With regards to her knee
replacement surgery, she is particularly worried
about post-operative pain.
As her primary surgeon what should you be
concerned of in this case?
A. There is a very high risk of chronic
regional pain syndrome (CRPS) in this
patient and she should be commenced on
vitamin C 1 month before her proposed surgery date
B. This patient can be a potential pain catastro-
phiser and her post-operative pain symptoms
should be quantified using a PCS quantification scale
C. This patient has post-traumatic stress dis-
order and should be referred for counselling
before surgery
D. This patient is at a high risk of suicide and
immediate psychiatric opinion should be
sought
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Oliver Bailey and Pradyumna Raval
E. This patient is normal and does not need
anything special. She should be listed for
surgery and post-operative pain managed as
per routine
61. In your elective clinic a 75-year-old wellcontrolled diabetic patient is consented for a total
knee arthroplasty. This patient has a history of
recurrent urinary tract infections in the past and
is currently awaiting a colonoscopy for irregular
bowel movements. His blood reports are within
normal limits.
With regards to haematogenous infectious
after a total knee arthroplasty, the rate of bacteraemia after invasive procedures is highest
with which of the following procedures?
A. Dental procedures
B. Ear and nasal procedures such as mastoidect-
omy and polypectomy
C. Gastrointestinal procedures such as
colonoscopy
D. Laparoscopic cholecystectomy
E. Urogenital procedures
62. Concerning knee examination tests to diagnose a
meniscal tear.
In which of the following tests does the joint
line tenderness change position with flexion
and extension?
A. Apley grind
B. Bragard
C. Duck walking
D. McMurray
E. Steinmann second
64. In a follow-up clinic you review a 26-year-old
young man who underwent ACL ligament
reconstruction 3 months ago. His primary complaint is inability to completely straighten his leg.
He tells you that he is still doing his exercises as
taught by the physiotherapist but is unable to
gain complete knee extension. On examination
his knee is stable, and you have no concerns
about graft stability. Clinically you feel that ‘graft
impingement’ has led to hi s symptoms.
Which of the following statements is false with
regards to ACL graft impingement?
A. Abnormal contact between ACL graft and
roof of the intercondylar notch on an MRI
scan
B. Increased signal intensity between distal two-
thirds of the graft on an MRI scan
C. Roof osteophytes abutting the ACL graft on
an MRI scan
D. The best radiograph for ACL graft impinge-
ment is a hyperextension lateral radiograph
E. The Multicenter ACL Revision Study
(MARS) group stated that approximately
30% of patients undergoing revision ACL
reconstruction had no impingement
65. A 17-year-old college student is referred to your
clinic with a complaint of recurrent patella dislocation. The patient’s symptoms are primarily
of locking and pain.
Figure 6.3
MRI scan knee
63. A 15-year-old school student is referred to your
elective knee clinic by his general practitioner
with a 3-month history of right knee pain. The
boy is a centre forward in his school football
team. He does not recollect any trauma to his
knee. Your examination reveals that he has a
stable knee. His blood investigations are within
normal limits. You perform a radiograph
followed by an MRI scan (Figure 6.3).
What is this image suggestive of?
A. Brodie’s abscess
B. FOPE (focal periphyseal oedema)
C. Osteochondritis dissecans
D. Osteoid osteoma
E. Salter Harris Type 1 injury
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Knee I Structured SBA
On examination of this patient how can you
clinically differentiate between a locking episode due to patellar pathology versus a locking
episode due to a meniscal tear?
A. Locking episodes due to patellar subluxation
and meniscal tear are similar and cannot be
differentiated on clinical examination
B. Locking episodes in patellar subluxation are
constant and painless
C. The knee is not able to flex or extend in a
locking episode because of patellar pathology
whereas in a bucket handle tear of meniscus
the knee can be further flexed
D. Pain is very well defined and located
posteriorly
E. In a bucket handle tear of meniscus there is
no restriction to terminal extension
66. A 56-year-old professor of economics presents to
the emergency department on a Saturday with a
bilateral knee injury while playing a game of
tennis. He tells you that he does not regularly
play tennis. On examination of his knees you
notice a bruise and swelling just proximal to
the knees and he is unable to do a straight leg
raise bilaterally.
What is the genetic link associated with the
injury of this patient?
A. COL1A2
B. COL1A1
C. COL5A1
D. GDF5
E. HOXB9
C. From full flexion to 45°, the load is shared
between tendinous portion of the extenso r
mechanism and the patella
D. The only component of the extensor mech-
anism in contact with the distal femur is the
patella at less than 45° of knee flexion
E. The terminal 15° of knee extension require
twice the torque required to extend the knee
from full flexion to 15°
68. An 18-year-old male is referred to your elective
knee clinic with an atraumatic history of right
knee pain. There is no significant past medical
history and all his blood investigations are within
normal limits. His MRI is shown in Figure 6.4.A
consultant radiologist has reported this as a
benign lesion and suggests imaging the other
knee to look for bilaterality.
A. Fibrous cortical defect
B. Osteoid osteoma
C. Dorsal defect of patella
D. Non-ossifying fibroma
E. Ewing’s sarcoma
67. A 45-year-old accountant presents to the ED
with a history of a fall while playing cricket.
The patient fell with a direct impact on his left
knee. Radiographs reveal that he has a patella
fracture.
With regards to the biomechanics of the patella,
which of the following statements is incorrect?
A. A decrease in the moment arm of the exten-
sor mechanism is caused by the patella by
anterior displacement from the knee’ s centre
of rotation
B. A total patellectomy can result in up to 50%
decrease in isokinetic strength testing of the
extensor mechanism
Figure 6.4 MRI scan knee
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Oliver Bailey and Pradyumna Raval
KNEE I STRUCTURED SBA ANSWERS
1. Answer C. Semitendinosus tendon
To accurately perform the posteromedial incision,
the semitendinosus tendon, flexion crease and
medial head of the gastrocnemius are used for
anatomical reference. In grossly swollen patients
with distorted anatomy, finding the semitendinosus tendon is an easy structure to identify and can
be helpful as it has fascial bands connecting it to
the medial head of the gastrocnemius muscle
thereby allowing you to confirm the correct plane
of dissection.
2. Answer E. Popliteus
The popliteus tendon is the most anterior femoral
attachment of the posterolateral corner and as per
Laprade (2014) in his anatomical dissections is on
average 18.5mm anterior to the femoral attachment of the LCL with the knee at 70° flexion
(Figure 6.5).
Figure 6.5
Popliteus tendon
considered to be part of the PMC. The PMC is
typically formed of 5 main components: the semimembranosus tendon and expansions, the oblique
popliteal ligament, the posterior oblique ligament,
the posteromedial joint capsule and the posterior
horn of the medial meniscus.
Dold AP, Swensen S, Strauss E, Alaia M. The
posteromedial corner of the knee: anatomy, pathology, and management strategies. J Am Acad
Orthop Surg. 2017;25:752–761.
4. Answer A. Common peroneal nerve
One of the first structures you should identify
when performing a PLC reconstruction is
the common peroneal nerve, which is at risk
of injury if not identified and protected
throughout.
The LCL and popliteus are useful to identify
and repair but not essential when performing a
reconstruction. The ITB is incised as part of the
approach. The tibial nerv e should not be seen
during this approach.
5. Answer B. 2–3 times body weight
The forces at the knee increase significantly with
increasing degrees of flexion. At about 45° of
flexion (needed to climb the stairs), joint reaction
forces are about 2–3 times body weight.
When walking on the flat, joint reaction forces
equal roughly 0.5 times body weight.
When squatting, joint reaction forces equal
roughly 7–8 times body weight.
When jumping, joint reaction forces can
increase to over 20 times body weight.
Masouros S, Bull A, Amis A. Biomechanics of
the knee joint. Orthop Trauma 2010;24:84–91.
Laprade RF et al. Improving outcomes for
posterolateral knee injuries. J Orthop Res.
2014;32:485–491.
3. Answer A. Medial collateral ligament
The superficial and deep portions of the MCL
function in close association with the structures
of the PMC; they are, however, not typically
120
6. Answer E. SF-30
The SF-36 is a popular general health outcome
measure; the SF-30 is not.
KOOS (Knee Injury and Osteoarthritis
Outcomes Score) is useful in evaluating soft tissue
knee injuries.
IKDC (International Knee Documentation
Committee) is useful in evaluating symptoms,
function and activity.
Lysholm Score was developed to evaluate knee
ligament surgery.
Oxford Knee Score was desig ned for patients
with knee arthritis.
Knee I Structured SBA
7. Answer B. Pigmented villonodular synovitis
Pigmented villonodular synovitis (PVNS) is a
benign proliferative condition of the synovial
membrane and tendon sheath. In the knee,
patients can present with a painless effusion and
symptoms of locking, catching and instability. It is
characterised by synovial inflammation and haemosiderin deposits.
Lipoma arborescens is a slow-growing benign
intra-articular lesion whereby the normal synovial
tissue is replaced by adipose tissue. The macroscopic appearance is like a tree, hence the Latin for
arborescens meaning ‘treelike’. It can present the
same way as PVNS, however the presentation is
more common in the middle to older aged group,
and most likely localised to one part of the joint
such as the suprapatella pouch unlike the MRI
demonstrated which is more generalised.
Patients with rheumatoid arthritis demonstrate generalised synovial hyperplasia with panus
formation on MRI. Other signs on MRI would be
subchondral cysts and erosions, juxta-articular
bone oedema, and decreased thickness of cartilage.
Synovial cell sarcoma is an intermediate to
high grade soft tissue sarcoma. Although the knee
is one of the most common sites for this tumour it
arises from the soft tissues surrounding the knee
rather than within the knee itself.
Synovial chondromatosis (otherwise called
Reichel syndrome) can be primary (unknown aetiology) or secondary (known aetiology such as
trauma, osteoarthritis or neuropathic arthropathy). This condition is characterised by abnormal
synovial growth of cartilage, which then breaks off
thereby creating floating bodies of cartilage which
if calcified can damage the joint further. The condition is most common in 30–50-year-old males.
8. Answer E. Outside-in meniscal repair kit
Typically, the anterolateral portal is placed blind;
therefore, to reduce iatrogenic injury to the anterior
horn of the lateral meniscus, this portal should be
placed high. Inferiorplacement risks creating aradial
tear in the anterior horn of the lateral meniscus.
Anterior horn tears are best approached from
outside-in, purely from a point of view of direction of instruments in relation to direction and
area of the tear. Anterior tears can also be
approached using inside-out techniques using an
introducer with a 90° curve, however this was not
part of the answer stem. Using an all-inside technique usually does not allow the surgeon to accurately position the repair sutures and is not the
preferred method.
Although chondral and ligament injuries can
occur with poor arthroscopic technique, these are
not the main risk with inferior placement of the
anterolateral portal.
9. Answer D. List for arthroscopy + saucerisation
+/– meniscocapsular repair
Three or more contiguous 5mm-thick sagittal
images of the meniscus from anterior to posterior
horns is suggestive of a discoid meniscus.
‘Snapping knee syndrome’ in the presence of a
discoid meniscus is suggestive of defective posterior meniscocapsular attachments, thus allowing
increased mobility of the meniscus.
The treatment of choice of symptomatic
patients is saucerisation and repair of the posterior
meniscocapsular deficiency if needed.
An asymptomatic discoid meniscus does not
require treatment.
10. Answer B. Discharge with no follow up
The MRI is suggestive of a discoid lateral meniscus. Having a minimal meniscal width to maximal tibial width (on coronal slice) of >20% and
having a ratio of the sum of the width of both
lateral horns to the maximal meniscal diameter
(on sagittal slice) >75% is highly suggestive of a
discoid meniscus (sensitivity 95% and specificity
97%). Other MRI findings of a discoid meniscus
is three or more 5mm-thick contiguous sagittal
slices from anterior to posterior horns.
Regardless of diagnosis, this is an incidental finding, and the asymptomatic patient can be
reassured and discharged.
11. Answer E. Tibial eminence hypoplasia
The MRI findings suggest a symptomatic lateral
discoid meniscus. Plain X-ray findings associated
witha lateral discoidmeniscusinclude(1) widening
of the lateral joint space, (2) squaring of the lateral
femoral condyle, (3) cupping of the lateral tibial
plateau and (4) tibial eminence hypoplasia.
12. Answer D. Popliteal artery injury
Drilling under X-ray guidance reduces the risk of
perforating too far into the popliteal fossa. Tibia
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Oliver Bailey and Pradyumna Raval
tunnel placement can be improved using X-ray;
however, it is mainly dictated by visualisation
through a posteromedial portal, clearance of the
PCL tibial footprint and usage of a PCL jig.
13. Answer B. You had not fully released the extra-
tendinous tethers to the medial head of
gastrocnemius
The hamstring tendons typically have extratendinous tethers that require release. This is particularly prevalent for the semitendinosus, which
quite reliably has a number of tethers between
itself and the medial head of gastrocnemius up to
10cm proximal from its distal attachment. If
these are not released prior to tendon stripping,
then the tendon stripper can follow the attachment rather than the true tendon, thereby amputating the tendon prematurely.
The Dial test is used to identify PCL and PLC
injuries clinically. This should be done preoperatively, as patients with a PLC injury that
has not been identified prior to ACL reconstruction have a higher rate of graft failure.
Both a closed loop tendon stripper and an
open loop stripper can be used to harvest the
graft.
A harvest wound that is small will make graft
harvest more difficult and will make it more
difficult to release the tethers; however, the
wound length is not the primary cause of graft
amputation.
Releasing the semitendinosus from the sartorial fascia can be done before or after graft
harvest.
14. Answer D. Hamstring autograft
The medial side of the foot is supplied by the
saphenous nerve. Saphenous nerve injury can be
a complication of hamstring graft harvest.
Possible complications with BTB autograft
would be patella fracture or persistent anterior
knee pain.
Possible complications with quadriceps autograft would be quadriceps rupture.
Possible complications with allograft are disease transmission and higher risk of re-rupture.
15. Answer B. The entry point for the tibial tunnel
is 2mm anterior to the anterior horn of the
lateral meniscus
The ideal tibial tunnel entry point is about 2mm
posterior to the anterior horn of the lateral
meniscus. If the tibial tunnel is too anterior, then
this can cause impingement in extension and an
extension block.
The entry point for the femoral tunnel is 2 or
10 o’clock (depending on the side). If the femoral
tunnel is too vertical, then this can lead to rotational instability of the graft rather than extension block.
Tensioning of the graft should ideally be
made in about 30° of knee flexion.
Cortical blowouts can occur during tunnel
reaming and are dealt with by changing your
fixation strategy; one such way is to use a larger
suspensory button (which rarely causes issues).
There are a number of different techniques to
deal with premature amputation of a hamstring
graft. One such way is to use an alternative graft
such as a bone–patella–tendon–bone graft. This
type of graft may have a larger diameter than a
proposed quadrupled hamstring therefore might
cause impingement issues, but these should not
occur if the tibial tunnel has an accurate
placement.
16. Answer A. The surgeon failed to address the
anterolateral complex
The anterolateral ligament complex is now
widely understood to be a secondary stabiliser
for the ACL for rotational stability. Injury of it
can be demonstrated radiographically by the
presence of a Segond fracture; however, the lack
of a Segond fracture does not mean the anterolateral complex is not injured. Sonnery-Cottet et
al. (2017) have shown a significantly reduced rate
of graft rupture in young patients returning to
pivoting sports when they have a combi ned ACL
and ALL reconstruction as opposed to an isolated ACL reconstruction. This is further backed
up by the results of the International
Anterolateral Complex Consensus Group
Meeting (Getgood et al. 2019).
The posterolateral complex is an important
structure to address if injured and would lead to
increased re-rupture rates if no t addressed; however, a negative Dial test would suggest the PLC
is intact.
A tibial graft tunnel that is too anterior can
lead to impingement in extension and graft
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failure; however, this is unlikely in this scenario
as the patient states they were happy during their
rehabilitation.
There is a lack of consensus as to the best type
of graft to use; both hamstring autograft and
patella tendon autograft are acceptable choices.
Sonnery-Cottet B et al. Anterolateral ligament
reconstruction is associated with significantly
reduced ACL graft rupture rates at a minimum
follow-up of 2 years: a prospective comparative
study of 502 patients from the SANTI Study
Group. Am J Sports Med. 2017;45:1547–1557.
Getgood A et al. The anterolateral complex
of the knee: results from the International ALC
Consensus Group Meeting. Knee Surg Sports
Trauma Arthroscopy 2019;27:166–176.
17. Answer B. Downsize the femur and use a
thicker insert
Downsizing the femur using anterior referencing
increases the flexion gap, thereby making this
knee looser in flexion. The flexion-extension
gap will therefore be loose in both flexion and
extension which can then be corrected by
inserting a thicker insert.
With regards to the other options, resecting
more bone off the femur will increase the extension gap (upsizing the femur will only change the
flexion gap or PFJ). Using distal femoral augments is an option; however, anteriorising the
femoral component will overstuff the PFJ and
cause a loose flexion gap. Resecting the PCL
increases the flexion gap however the question
states a PS technique is used therefore the PCL
should already be released. Resecting more bone
off the tibia will increase the flexion and extension gap and will not balance the knee.
18. Answer E. Upsize the femur
If you have a loose knee in flexion, all of the
following will reduce the flexion gap: Upsizing the
femur using anterior referencing, using a thicker
insert, posteriorising the femoral component.
Proximalising the femur and using a thicker
insert will balance the knee; however, proximalising the femur is a bigger undertaking than
upsizing the femur. Posteriorising the femoral
component will notch the femur if using anterior
referencing and therefore is not recommended.
19. Answer B. CT rotational profile of the leg
The history is not really pointing you towards
a diagnosis of infection (although this should
remain a potential diagnosis). Someone who
has no history of infection or trauma and states
they were ‘ never really happy’ with their knee
should point you towards malrotation of the
components. Bell et al. (201 4) demonstrate
that internal rotation of the tibial or femoral
components in creases the risk of ongoing knee
pain. One reason for internal rotation leading
to poor outcomes is that this interferes with
patella tracking in a negative way, increasing
lateral patella facet wear, clunking and anterior
knee pain.
Bell SW et al. Component rotational align-
ment in unexplained painful primary total knee
arthroplasty. Knee 2014;21:272–277.
20. Answer D. Release the popliteus
In a valgus knee, the following lateral compartment release maybe required: (1) osteophytes, (2)
lateral capsule, (3) iliotibial band, (4) popliteus.
The LCL can be released; however, if you are
requiring to do this, you should be thinking
about increased constraint.
Release of the PCL, downsizing the femoral
component and resecting more off the tibia will
universally increase the flexion gap; however, in
this case it is only tight laterally in flexion.
21. Answer D. On measuring the femoral com-
ponent size using post erior referencing, it
measured 4.5 and the dec ision was made to
use a size 4 implant, as a size 5 may overstuff
the PFJ
When using posterior referencing, the femoral
component size is measured referenced off the
posterior femoral condyles. If downsizing (as in
this case), then you risk notching the femur,
which introduces a point of weak bone and
increases the risk of periprosthetic knee fractures. When using posterior referencing and
wanting to downsize the femoral component,
then anteriorising the cutting jig will mitigate
the risk of notching; however, doing so carries
the risk of overstuffing the PFJ.
All other responses are valid intraoperative
decisions.
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